Expression of Arabidopsis <i>CAX2</i> in Tobacco. Altered Metal Accumulation and Increased Manganese Tolerance

Hirschi, Kendal D.; Korenkov, Victor; Wilganowski, Nathaniel; Wagner, George J.

doi:10.1104/pp.124.1.125

Cited by 428 publications

(277 citation statements)

References 36 publications

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“…1996, 2000; Ueoka‐Nakanishi et al . 1999), recent studies are beginning to implicate CAXs in a range of cellular and physiological processes, including stomatal function via cellular pH regulation, phosphate starvation signalling and hypoxia.…”

Section: Resultsmentioning

confidence: 99%

“…While some CAXs can mediate trace metal ion transport, and therefore potentially provide tolerance to metal stress via direct metal sequestration (Hirschi et al . 2000; Korenkov et al . 2007; Edmond et al .…”

Section: The Cax Transporters In Abiotic Stress Signallingmentioning

confidence: 99%

“…Thus it has been proposed that a primary cellular function of the CAX proteins is to restrict cytosolic accumulation of certain free metal ions, such as Mn 2+ or Cd 2+ to provide tolerance against metal toxicity, and to maintain a low cytosolic resting concentration of Ca 2+ to prevent Ca 2+ toxicity and prime the generation of cytosolic Ca 2+ signals (Hirschi et al . 2000; McAinsh & Pittman 2009). Although CAXs are just one class of ion transporter able to mediate such housekeeping functions, a wealth of evidence now indicates their importance to plants, especially during abiotic stress.…”

Section: Introductionmentioning

confidence: 99%

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CAX‐ing a wide net: Cation/H⁺ transporters in metal remediation and abiotic stress signalling

2016

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Cation/proton exchangers (CAXs) are a class of secondary energised ion transporter that are being implicated in an increasing range of cellular and physiological functions. CAXs are primarily Ca2+ efflux transporters that mediate the sequestration of Ca2+ from the cytosol, usually into the vacuole. Some CAX isoforms have broad substrate specificity, providing the ability to transport trace metal ions such as Mn2+ and Cd2+, as well as Ca2+. In recent years, genomic analyses have begun to uncover the expansion of CAXs within the green lineage and their presence within non‐plant species. Although there appears to be significant conservation in tertiary structure of CAX proteins, there is diversity in function of CAXs between species and individual isoforms. For example, in halophytic plants, CAXs have been recruited to play a role in salt tolerance, while in metal hyperaccumulator plants CAXs are implicated in cadmium transport and tolerance. CAX proteins are involved in various abiotic stress response pathways, in some cases as a modulator of cytosolic Ca2+ signalling, but in some situations there is evidence of CAXs acting as a pH regulator. The metal transport and abiotic stress tolerance functions of CAXs make them attractive targets for biotechnology, whether to provide mineral nutrient biofortification or toxic metal bioremediation. The study of non‐plant CAXs may also provide insight into both conserved and novel transport mechanisms and functions.

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Section: Resultsmentioning

confidence: 99%

Section: The Cax Transporters In Abiotic Stress Signallingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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CAX‐ing a wide net: Cation/H⁺ transporters in metal remediation and abiotic stress signalling

2016

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“…Members of the CAX transporter family are able to facilitate Cd 2+ transport [15]. In our study, we have identified two members of the CAX family, OsCAX1a (closest Arabidopsis homologue is At3g51860) and AtCAX5 (At1g55720).…”

Section: A Cax-transporter Homolog Is Upregulated Under Low CD 2+mentioning

confidence: 91%

“…In Saccharomyces cerevisiae, a MRP-type ABC transporter has been shown to transport bisglutathione-Cd 2+ , while in Schizosaccharomyces pombe, HMT1, a half size ABC transporter transports phytochelatin-Cd 2+ . In plants, evidence has been presented that at least one member of the CAX family exhibits a Cd 2+ -proton antiport activity [15]. Furthermore, transport studies suggest that an ABC transporter is responsible for the vacuolar phytochelatin transport [16].…”

Section: Introductionmentioning

confidence: 99%

Quantitative detection of changes in the leaf‐mesophyll tonoplast proteome in dependency of a cadmium exposure of barley (Hordeum vulgare L.) plants

et al. 2009

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Although the vacuole is the most important final store for toxic heavy metals like cadmium (Cd(2+)), our knowledge on how they are transported into the vacuole is still insufficient. It has been suggested that Cd(2+) can be transported as phytochelatin-Cd(2+) by an unknown ABC transporter or in exchange with protons by cation/proton exchanger (CAX) transporters. To unravel the contribution of vacuolar transporters to Cd(2+) detoxification, a quantitative proteomics approach was performed. Highly purified vacuoles were isolated from barley plants grown under minus, low (20 microM), and high (200 microM) Cd(2+ )conditions and protein levels of the obtained tonoplast samples were analyzed using isobaric tag for relative and absolute quantitation (iTRAQ). Although 56 vacuolar transporter proteins were identified, only a few were differentially expressed. Under low-Cd(2+) conditions, an inorganic pyrophosphatase and a gamma-tonoplast intrinsic protein (gamma-TIP) were up-regulated, indicating changes in energization and water fluxes. In addition, the protein ratio of a CAX1a and a natural resistance-associated macrophage protein (NRAMP), responsible for vacuolar Fe(2+) export was increased. CAX1a might play a role in vacuolar Cd(2+) transport. An increase in NRAMP activity leads to a higher cytosolic Fe(2+) concentration, which may prevent the exchange of Fe(2+) by toxic Cd(2+). Additionally, an ABC transporter homolog to AtMRP3 showed up-regulation. Under high Cd(2+) conditions, the plant response was more specific. Only a protein homologous to AtMRP3 that showed already a response under low Cd(2+) conditions, was up-regulated. Interestingly, AtMRP3 is able to partially rescue a Cd(2+)-sensitive yeast mutant. The identified transporters are good candidates for further investigation of their roles in Cd(2+) detoxification. AbstractAlthough the vacuole is the most important final store for toxic heavy metals like cadmium (Cd 2+ ), our knowledge on how they are transported into the vacuole is still scarce. It has been suggested that Cd 2+ can be transported either as phytochelatin-Cd 2+ by an unknown ABC transporter or in exchange with protons by CAX transporters. To unravel the contribution of vacuolar transporters to Cd 2+ detoxification, a quantitative proteomics approach was performed.Highly purified vacuoles were isolated from barley plants grown under minus, low (20 µM), and high (200 µM) Cd 2+ conditions and protein levels of the obtained tonoplast samples were analyzed using iTRAQ TM . Although, 56 vacuolar transporter proteins were identified, however only a few were differentially expressed. Under low-Cd 2+ conditions an inorganic pyrophosphatase and a γ-tonoplast intrinsic protein (γ-TIP) were upregulated, indicating changes in energization and water fluxes. In addition, the protein ratio of a calcium/proton exchanger (CAX1a) and an NRAMP, responsible for vacuolar Fe 2+ export were increased. CAX1a might play a role in vacuolar Cd 2+ transport. An increase in NRAMP activity leads to a higher cytosol...

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Iron Bioavailability, Homeostasis through Phytoferritins and Fortification Strategies: Implications for Human Health and Nutrition

Nirupa

Prasad

2008

Trace Elements as Contaminants and Nutrients

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Expression of Arabidopsis CAX2 in Tobacco. Altered Metal Accumulation and Increased Manganese Tolerance

Cited by 428 publications

References 36 publications

CAX‐ing a wide net: Cation/H⁺ transporters in metal remediation and abiotic stress signalling

CAX‐ing a wide net: Cation/H⁺ transporters in metal remediation and abiotic stress signalling

Quantitative detection of changes in the leaf‐mesophyll tonoplast proteome in dependency of a cadmium exposure of barley (Hordeum vulgare L.) plants

Iron Bioavailability, Homeostasis through Phytoferritins and Fortification Strategies: Implications for Human Health and Nutrition

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Expression of Arabidopsis CAX2 in Tobacco. Altered Metal Accumulation and Increased Manganese Tolerance

Cited by 428 publications

References 36 publications

CAX‐ing a wide net: Cation/H+ transporters in metal remediation and abiotic stress signalling

CAX‐ing a wide net: Cation/H+ transporters in metal remediation and abiotic stress signalling

Quantitative detection of changes in the leaf‐mesophyll tonoplast proteome in dependency of a cadmium exposure of barley (Hordeum vulgare L.) plants

Iron Bioavailability, Homeostasis through Phytoferritins and Fortification Strategies: Implications for Human Health and Nutrition

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Resources

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CAX‐ing a wide net: Cation/H⁺ transporters in metal remediation and abiotic stress signalling

CAX‐ing a wide net: Cation/H⁺ transporters in metal remediation and abiotic stress signalling